Horrible Lag, even in menu's, after 6.0 update?

What did you guys change that killed my FPS?

I used to get 20-25FPS on average and it was steady.
After the 6.0 update I've been getting 10 or less extremely stuttery FPS.

Please say you didn't optimize further for high end proccesors that already had acceptable performance? The general rule of optimization is get the game playable on all reasonably supported CPU's (The minnimum is a dual core 2nd gen i3 last i checked, seeing as how i have a Quad Core which outperforms it in CPU benchs such as cinebench) and then optimize for the higher end stuff.

Even the menu is lagging (It actually lags worse in the menu than in game).

Whatever you guys did its a performance killer and you've effectively made the game unplayable for me and i have no way to roll back to the 5.0 line that was playable.